Electrical Junction Box

This application is the U.S. national stage of PCT/JP2023/020156 filed on May 30, 2023, which claims priority of Japanese Patent Application No. JP 2022-096065 filed on Jun. 14, 2022, the contents of which are incorporated herein.

The present disclosure relates to an electrical junction box containing electronic components.

Conventionally, electrical junction boxes containing electronic components such as fuses and relays are mounted on vehicles.

An electrical junction box includes a housing. For example, the housing is composed of a first case that is open on one side and contains electronic components, and a second case that covers the open side of the first case (see JP 2016-208561A).

For example, a large current flows through an electronic component such as a relay when an electrical junction box is operated. There is a risk of electric shock when an operator's fingers touch a contact portion of the relay. Malfunctions such as electric shock can be prevented by covering the contact portion of the relay with a cover member.

Since a large current flows through the relay, heat is generated at the relay and its contact portion. In the case where the contact portion of the relay is covered with the cover member as mentioned above, the heat tends to build up inside the cover member. That is, the air inside the cover member removes the heat from the relay and its contact portion and moves, but is not released to the outside due to the cover member. This causes accumulation of hot air inside the cover member. If heat builds up inside the cover member, the cover member and the surrounding insulating resin components may wear and lose their insulation, causing malfunctions such as short circuits.

With the electrical junction box in JP 2016-208561A, such problems are not taken into consideration and cannot be solved.

The present disclosure therefore has an object of providing an electrical junction box that can prevent heat from a contact portion of an electronic component from building up while covering the contact portion to prevent the contact portion from being exposed.

An electrical junction box according to an embodiment of the present disclosure is an electrical junction box including: a housing containing an electronic component that generates heat when energized; and a cover member that covers a terminal provided on a side surface of the electronic component, and that covers a surrounding area of the terminal, wherein the cover member has an air vent that allows airflow inside and outside of the cover member.

According to the present disclosure, it is possible to prevent heat from a contact portion of an electronic component from building up while covering the contact portion to prevent the contact portion from being exposed.

First, embodiments of the present disclosure will be listed and described. The embodiments described below may be at least partly combined in any way.

An electrical junction box according to an embodiment of the present disclosure is an electrical junction box including: a housing containing an electronic component that generates heat when energized; and a cover member that covers a terminal provided on a side surface of the electronic component, and that covers a surrounding area of the terminal, wherein the cover member has an air vent that allows airflow inside and outside of the cover member.

In this embodiment, the cover member covers the terminal provided on the side surface of the electronic component and its surrounding area, and the air vent of the cover member allows airflow inside and outside of the cover member. Thus, heat from the contact portion of the electronic component can be prevented from building up inside the cover member while the contact portion is covered and prevented from being exposed.

In the electrical junction box according to an embodiment of the present disclosure, the electronic component is mounted on a pedestal provided in the housing, the cover member includes a facing plate that faces the side surface of the electronic component, and an electric shock prevention plate that is provided at an edge of the facing plate located apart from the housing and shields a gap between the facing plate and the side surface to prevent electric shock, and the air vent includes a first air vent formed in the electric shock prevention plate.

In this embodiment, the electric shock prevention plate shields the gap between the facing plate of the cover member and the side surface of the electronic component to prevent electric shock, and the first air vent formed in the electric shock prevention plate allows airflow inside and outside of the cover member. Thus, heat from the contact portion of the electronic component can be prevented from building up inside the cover member while the contact portion is covered to prevent electric shock due to exposure of the contact portion.

In the electrical junction box according to an embodiment of the present disclosure, the first air vent is formed at one edge of the electric shock prevention plate closer to the side surface of the electronic component.

In this embodiment, the first air vent is formed at one edge closer to the side surface of the electronic component. In other words, the first air vent is formed above the contact portion of the electronic component, that is, in the path of rising air that has absorbed heat from the contact portion and become hot. Hence, hot air is quickly released to the outside of the cover member, and heat from the contact portion can be prevented from building up inside the cover member.

In the electrical junction box according to an embodiment of the present disclosure, the air vent includes a second air vent formed in the electric shock prevention plate apart from the one edge.

In this embodiment, the second air vent is formed in the electric shock prevention plate at a position located apart from the one edge, in addition to the first air vent. Hence, hot air inside the cover member is more quickly released to the outside of the cover member, and heat from the contact portion can be more effectively prevented from building up inside the cover member.

In the electrical junction box according to an embodiment of the present disclosure, the first air vent has a comb shape that is open toward another edge opposite to the one edge.

In this embodiment, the first air vent has a comb shape that is open toward the other edge opposite to the one edge. Thus, the air vent for releasing hot air inside the cover member to the outside of the cover member is expanded while ensuring that electric shock due to exposure of the contact portion of the electronic component is prevented.

In the electrical junction box according to an embodiment of the present disclosure, the air vent includes a third air vent formed in the facing plate.

In this embodiment, the third air vent is formed in the facing plate of the cover member, and therefore outside air flows into the cover member through the third air vent. This shortens the circulation of air inside and outside the cover member, making it possible to increase the efficiency of heat dissipation by releasing hot air inside the cover member to the outside.

In the electrical junction box according to an embodiment of the present disclosure, the pedestal includes a clamping mechanism that clamps the facing plate, and the facing plate has an engagement protrusion that engages with an engagement portion formed in the clamping mechanism.

In this embodiment, when the cover member is attached, the clamping mechanism clamps the facing plate of the cover member, and the engagement protrusion of the facing plate engages with the engagement portion of the clamping mechanism. This prevents the cover member from being unintentionally removed.

Electrical junction boxes according to embodiments of the present disclosure will be described below, with reference to the drawings. The present disclosure is not limited to these examples, but is defined by the claims and intended to include all modifications within the meaning and scope equivalent to the claims.

is a perspective view of an electrical junction boxaccording to Embodiment 1.are a plan view and a side view of the electrical junction boxaccording to Embodiment 1.is a plan view of the electrical junction box, andis a side view of the electrical junction box.

The electrical junction boxis attached to the outside of an attachment object, such as a battery pack(see) of an electric vehicle (EV).shows the electrical junction boxattached to the battery pack, for the sake of convenience.

The electrical junction boxincludes a housingcontaining fuses, substrates, and the like. The housingis flat and approximately rectangular in plan view, with one corner of one end in the length direction cut out in a stepped shape. The housingis made of, for example, resin, and includes a lower casethat is attached to the attachment object and an upper casethat covers the lower case. In the following description, it is assumed that the upper caseside is the upper side and the lower caseside is the lower side, for the sake of convenience.

The lower casehas a box shape that is open on the upper caseside. The upper casehas a box shape that is open on the lower caseside. The upper caseis slightly larger than the lower casein the length direction and in the width direction orthogonal to the length direction, and covers the lower case.

The lower casehas a bottom wallwhose outer surface comes into contact with the attachment object, and a side wallthat extends vertically from the edges of the bottom wallto the upper caseside.

The upper casehas a ceiling wallthat faces the bottom wallof the lower case, and a side wallthat is provided along the edges of the ceiling walland extends vertically to the lower caseside. The upper caseis provided with fastening portionsfor attaching the housingto the attachment object, at both ends and at an intermediate portion in the length direction.

That is, fastening portionsare provided at both corners of one end in the length direction, and at both corners and between the corners of the other end in the length direction. Further, at an intermediate portion of the upper casein the length direction, three fastening portionsare arranged in the width direction. Each fastening portionprotrudes from the inner surface of the ceiling wallfacing the bottom wall. The fastening portionsexcept for one fastening portionlocated approximately at the center of the ceiling wallare located near the side wall(see).

Each fastening portionhas a bottomed cylindrical shape and is open on the ceiling wallside. A through hole (not shown) used when attaching the housingto the attachment object is formed at the bottom of each fastening portion. The housing(electrical junction box) can be attached to the attachment object by inserting a screw from the attachment object into the through hole of each fastening portionand screwing it into a nut (not shown) provided in the fastening portion.

A plurality of ribsprotrude from the outer surfaceof the ceiling wallopposite to the inner surface, in order to prevent warping of the ceiling walldue to gravity, differences in thermal expansion, and the like.

Moreover, various connection portionsfor connection to other devices are arranged at a plurality of locations on the outer surfaceof the ceiling wall. Further, at approximately the center of the outer surfaceof the ceiling wall, a plurality of mounting seats(pedestals) for relays(electronic components) are arranged and the relaysare mounted on the respective mounting seats.

Each relayis connected to a bus bar(described later). The contact portion between the bus barand the relayis covered with a cover member.

is a partially enlarged perspective view showing a state in which the cover memberis attached in the electrical junction boxaccording to Embodiment 1.is a partially enlarged perspective view showing a state in which the cover memberis removed in the electrical junction boxaccording to Embodiment 1.

The mounting seatis a recess that is rectangular in plan view. That is, in the mounting seat, a plate material stands upward from each edge of the rectangular bottom surface(see). The relayhas a rectangular parallelepiped shape, and is mounted on the mounting seatfrom the bottom side, with the upper surfaceexposed. The cover memberis attached between the relayand the mounting seat.

The relayhas two terminalslaterally spaced apart from each other, on one surface(side surface). The bus baris connected to each terminal. Each terminalis cylindrical with a threaded portion formed on the inner circumferential surface, and only one end is exposed from the one surfaceand the remaining part is embedded in the relay. The bus baris screwed to the terminalby inserting a boltthrough a through hole formed at one end of the bus barand screwing the boltto the terminal. A strip-shaped shielding plateextending vertically protrudes from the center of the one surfacebetween the two terminals.

The relayalso has an engagement protrusionthat engages with an engaged portion(described later) of the mounting seat, on a side surfaceadjacent to the one surface.

The mounting seathas a rectangular plate portionfacing the one surfaceof the relay. The rectangular plate portionhas a cutout in an intermediate portion corresponding to the terminalsof the relay, excluding both endsin the lateral direction. An engagement grooveis provided between both endsat a position corresponding to the shielding plateof the relay. The inside of the engagement groovecorresponds in shape to the shielding plate, and engages with the shielding plate. The engagement grooveis shorter than the shielding platein the vertical direction, with both ends open. Therefore, the upper end of the shielding platesticks out of the upper end of the engagement groove(see).

Each endof the rectangular plate portionhas a notch(engagement portion) that engages with an engagement protrusion(described later) of the cover member. The notchis a rectangle extending vertically. The endforms a clamping mechanismtogether with a clamping pillar. The clamping pillarand the clamping mechanismwill be described in detail later.

In the mounting seat, an open portionis provided in an intermediate portion in the lateral direction of the plate portion adjacent to the rectangular plate portion. The open portionis provided with the engaged portionthat engages with the engagement protrusionof the relay. The engaged portionhas an inverted U-shape. The engagement between the engaged portionand the engagement protrusioncauses the relayto be held on the mounting seat.

In the mounting seat, the clamping mechanismsfor clamping the cover memberare provided at both ends of the rectangular plate portion. Each clamping mechanismis composed of the endof the rectangular plate portionand the clamping pillar, as mentioned above. The two clamping pillarshave the same shape.

is a schematic vertical sectional view of the clamping mechanismin a state in which the cover memberis attached in the electrical junction boxaccording to Embodiment 1.is a sectional view taken along arrowis a schematic vertical sectional view of the clamping VI in. mechanismin a state in which the cover memberis removed in the electrical junction boxaccording to Embodiment 1.is a schematic vertical sectional view of the electrical junction boxaccording to Embodiment 1 with the cover memberand the rectangular plate portionof the mounting seatomitted.shows the state in which the boltand the bus barare removed, for the sake of convenience.

Each clamping pillarprotrudes from the bottom surfaceof the mounting seat, on the inner side of the corresponding endand apart from the end(see). Each clamping pillaris a flat rectangular parallelepiped housing extending vertically, and is open on the bottom surfaceside.

Both main surfaces of the clamping pillarface the endand the relay. Of the two main surfaces, one main surface on the relayside is open, with an upper endprovided at the top. The one end of the bus baris inserted between the clamping pillarand the one surfaceof the relayfrom below and is positioned by the upper end(see).

The other main surface of the clamping pillarhas a biasing portionraised by making a cut along each side wallnear the side wallThe biasing portionis shorter than the side wallon the lower side, and has the lower end protruding to the endside. As shown in, the biasing portionis located at a position corresponding to the notchof the end

are perspective views showing the cover memberof the electrical junction boxaccording to Embodiment 1.is a perspective view showing the front side of the cover member.is a perspective view showing the back side of the cover member. The cover memberis made of, for example, an insulating material, and covers the contact portion on the one surfaceof the relayas mentioned above. That is, the cover membercovers approximately the entire one surface, including each terminal(bolt) of the relayand one end of the bus barconnected to the terminal.